Spindle drive assembly, vehicle flap with a spindle drive assembly and method for installing a spindle drive assembly

ABSTRACT

A spindle drive assembly for opening and/or closing a vehicle flap including a spindle drive assembly housing extending along a spindle drive axis and, between its axial ends, a stop section acting axially on both sides. A motor gear unit is arranged on a first side of the stop section and a spindle unit is arranged on a second side of the stop section. Furthermore, a vehicle flap with such a spindle drive assembly. In addition, a method of assembling a spindle drive assembly.

The invention relates to a spindle drive assembly for opening and/or closing a vehicle flap.

The invention further relates to a vehicle flap, in particular a vehicle hatch or tailgate or a vehicle trunk lid, with such a spindle drive assembly.

In addition, the invention relates to a method of assembling a spindle drive assembly of the above-mentioned type.

BACKGROUND OF THE INVENTION

Vehicle flaps and spindle drive assemblies of the type initially mentioned are known from the prior art.

The known spindle drive assemblies generally comprise an electric spindle drive by means of which the associated vehicle flap can be opened and/or closed. This means that a user of an associated vehicle no longer needs to carry out the opening and closing manually. The user only needs to send an open or close command to the spindle drive assembly, which he or she can do, for example, via a radio remote control or via a switch arranged in the vehicle. A foot switch which is arranged on the outside of the vehicle and can operate without contact can also be used.

In order to protect in particular the electrical components of the spindle drive assembly from environmental influences such as, e.g., moisture and dust, the spindle drive assemblies are usually encased when they are mounted to a vehicle flap.

In the field of the manufacture of spindle drive assemblies, the aim is to keep the assembly of the spindle drive assembly as simple and cost-effective as possible. However, this causes a conflict of objectives with a reliable encasing or enclosure, so that a spindle drive assembly that is simple and cost-effective to assemble generally offers only moderate protection from environmental influences.

SUMMARY OF THE INVENTION

The object of the invention is to overcome this conflict of objectives and to indicate a spindle drive assembly which can be assembled in a simple and cost-effective manner and also provides a particularly effective protection of the spindle drive assembly components against environmental influences.

The object is achieved by a spindle drive assembly of the type initially mentioned, in which a spindle drive assembly housing extends along a spindle drive axis and the spindle drive assembly housing includes, between its axial ends, a stop section acting axially on both sides, a motor gear unit being arranged on a first axial side of the stop section and a spindle unit being arranged on a second axial side of the stop section opposite the first axial side. The motor gear unit here includes an electric spindle drive motor and a gearing coupled thereto. In addition, it may optionally also comprise a brake, one or more sensors and/or an overload safety device. The spindle unit comprises at least one spindle and a spindle nut coupled thereto. The stop section provides for a defined position of the motor gear unit and the spindle unit within the spindle drive assembly housing. This applies both during operation and during assembly. The spindle drive assembly housing is preferably tubular and has a substantially circular cross-section. Therefore, that part in which the motor gear unit and the spindle unit are seated can preferably be manufactured in one piece, so that these components are particularly well protected against environmental influences. This results from the absence of contact surfaces or contact lines between different components of the spindle drive assembly housing in this region. Such contact surfaces or lines constitute weak points with respect to undesirable environmental influences. In addition, such a spindle drive assembly is particularly simply constructed and therefore simple and cost-effective to assemble.

Preferably, the spindle drive assembly housing comprises a housing cap, which closes the spindle drive assembly housing on the motor gear unit side, the housing cap being more particularly laser welded inside the spindle drive assembly housing. Such a housing cap provides a particularly simple closure of the spindle drive assembly housing. Furthermore, the housing cap reliably seals the spindle drive assembly housing and in this way ensures an effective protection of the components contained in the spindle drive assembly housing against any undesirable environmental influences. This is particularly the case if the housing cap is laser welded. An associated laser weld seam constitutes a watertight and dustproof connection. Preferably, the laser weld seam here fully surrounds a circumference of the housing cap, so that the housing cap reliably seals the end of the spindle drive assembly housing. It is further preferred that the laser weld seam is circumferential through at least 361 degrees. This provides a particularly highly reliable protection against undesirable environmental influences. Thus, the spindle drive assembly housing is watertight.

Preferably, a mechanical interface to a vehicle body is arranged on the housing cap and includes ball sockets or stop means, for example. The housing cap may also have an electrical interface provided thereon, which includes a cable lead-through, for example.

According to one embodiment, the motor gear unit is supported in the spindle drive assembly housing so as to be rotationally fixed with respect to the spindle drive axis, in particular wherein the motor gear unit is supported in the spindle drive assembly housing by means of a damping element or by means of a plurality of damping elements. Preferably, the motor gear unit is supported in the spindle drive assembly housing by means of an interlocking fit. In this way, the rotationally fixed mounting is achieved by simply inserting the motor gear unit into the spindle drive assembly housing. The assembly process is therefore particularly simple. Here, the rotationally fixed mounting of the motor gear unit serves for torque support.

A respective damping element, e.g. made from an elastomer, may be provided at each of the two axial ends of the motor gear unit, the aforementioned interlocking fit being implemented by means of the damping element. Accordingly, the driving torque of the motor gear unit is supported axially at the front and axially at the rear.

The spindle unit may comprise a guide tube fastened in the spindle drive assembly housing, in particular wherein the guide tube and the spindle drive assembly housing are laser welded. The guide tube ensures a precise and reliable guidance of the spindle nut. It may be in the form of a plain bearing bush. The fastening of the guide tube to the spindle drive assembly housing is preferably made to be watertight, so that there is no possibility of undesirable environmental impact on the components of the spindle drive assembly at this point. This is particularly the case if the guide tube and the spindle drive assembly housing are laser welded. An associated laser weld seam preferably is fully circumferential and, more preferred, is circumferential through at least 361 degrees, thus effecting a particularly reliable sealing of the spindle drive assembly housing against any undesirable environmental influences. In particular, the spindle drive assembly housing is watertight.

Preferably, the guide tube is made from a plastic material.

Advantageously, the stop section is manufactured in one piece with the spindle drive assembly housing. The spindle drive assembly housing can therefore be manufactured with particularly little effort and at particularly low cost.

The spindle drive assembly housing may be produced by injection molding, for example.

The spindle drive assembly housing is preferably made from plastic. This material is watertight and dustproof. It is therefore particularly well suited for protecting the components of the spindle drive assembly from environmental influences. Also, plastic materials can be processed easily and cost-effectively using standard machines, so that the spindle drive assembly can also be manufactured simply and cost-effectively.

Furthermore, the object is achieved by a vehicle flap of the type initially mentioned, in particular a vehicle hatch or tailgate or vehicle trunk lid, which includes a spindle drive assembly according to the invention. Since the spindle drive assembly is structured in a simple and cost-effective manner, a vehicle flap fitted with it is consequently also structured to be comparatively simple and cost-effective. Moreover, such a vehicle flap is particularly reliable in operation because the spindle drive assembly is particularly well protected against undesirable environmental influences.

In addition to the above-mentioned vehicle flaps, luggage flaps or tailgates of sport utility vehicles or commercial vehicles may also be fitted with a spindle drive assembly according to the invention. The same applies to engine hoods and vehicle front gates.

Additionally, the object is achieved by a method of the type initially mentioned, which includes the steps of:

-   -   (a) providing a spindle drive assembly housing extending along a         spindle drive axis;     -   (b) inserting a motor gear unit into the spindle drive assembly         housing starting from a first axial side of the spindle drive         assembly housing; and     -   (c) inserting a spindle unit into the spindle drive assembly         housing starting from a second axial side of the spindle drive         assembly housing opposite the first.

This means that the motor gear unit and the spindle unit are inserted into the spindle drive assembly housing from opposite sides. The spindle drive assembly housing is therefore particularly well accessible for assembly. Furthermore, this allows the motor gear unit and the spindle unit to be inserted into the spindle drive assembly housing at the same time or overlapping in time. As a result, assembly can be effected particularly quickly in time. All in all, a simple and cost-effective assembly is thus achieved.

A stop section acting axially on both sides may be provided at the spindle drive assembly housing and the motor gear unit may be placed against a first axial side of the stop section. In this way, the motor gear unit is simply and reliably positioned in the spindle drive assembly housing. Any subsequent alignment or adjustment is not necessary.

In an alternative, the motor gear unit is mounted in the spindle drive assembly housing in a rotationally fixed manner, in particular wherein the motor gear unit is mounted in the spindle drive assembly housing with an interlocking fit. Here, the interlocking mounting may comprise one or more damping elements. In this case, first the damping elements are fixed on the motor gear unit and then the component assembly made up of the motor gear unit and the damping elements is mounted in the spindle drive assembly housing. The interlocking mounting allows subsequent fastening steps, in particular those serving to support a driving torque of the motor gear unit, to be dispensed with.

Preferably, a first damping element is fixed to an end of the motor gear unit that is axially at the front and a second damping element is fixed to an end that is axially at the rear.

The damping elements are made from an elastomer, for example.

In one embodiment, a stop section acting axially on both sides is provided at the spindle drive assembly housing, and the spindle unit is placed against a second axial side of the stop section opposite the first axial side. In this way, the spindle unit is positioned simply and reliably within the spindle drive assembly housing. Any subsequent alignment or adjustment is not necessary here, either.

Preferably, the spindle unit is fastened to the spindle drive assembly housing, in particular wherein the spindle unit is laser welded to the spindle drive assembly housing. In this way, the spindle unit is reliably held in its intended position. In addition, the laser weld seam produces a seal against any undesirable environmental influences, which in particular is watertight. Preferably, the laser weld seam is fully circumferential. More preferably, it encircles the circumference through at least 361 degrees.

A guide tube comprised by the spindle unit may also be fastened to the spindle drive assembly housing, in particular wherein the guide tube is laser welded to the spindle drive assembly housing.

In one variant, a housing cap is placed on the spindle drive assembly housing on the motor gear unit side, so that the housing cap closes the spindle drive assembly housing.

In this context, the housing cap may be fastened inside the spindle drive assembly housing, in particular laser welded inside the spindle drive assembly housing.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be discussed below with reference to an exemplary embodiment shown in the accompanying drawings, in which:

FIG. 1 schematically shows a vehicle flap according to the invention with a spindle drive assembly according to the invention that is assembled by means of a method according to the invention;

FIG. 2 shows the spindle drive assembly from FIG. 1 in a schematic sectional view;

FIG. 3 shows the spindle drive assembly from FIG. 1 in an exploded representation;

FIG. 4 shows the spindle drive assembly from FIG. 1 in a sectional detail view;

FIG. 5 shows a spindle drive motor of the spindle drive assembly from FIG. 1 in a perspective view;

FIG. 6 schematically shows the interaction of the spindle drive motor from FIG. 5 with a spindle drive assembly housing in a partly sectional illustration;

FIG. 7 schematically shows an end view of the spindle drive motor from FIGS. 5 and 6 and of a housing cap adapted to be connected with the spindle drive motor;

FIG. 8 shows an exploded illustration of a two-stage epicyclic gearing of the spindle drive assembly from FIG. 1 , which can be assembled by means of a method according to the invention;

FIG. 9 shows a further exploded illustration of the two-stage epicyclic gearing of the spindle drive assembly from FIG. 1 , with the epicyclic gearing partly assembled by means of a method according to the invention;

FIG. 10 shows an exploded illustration of the spindle drive assembly from FIG. 1 , comprising a two-stage epicyclic gearing, a coupling, a hysteresis brake and a spindle drive motor;

FIG. 11 shows a spindle unit of the spindle drive assembly from FIG. 1 in an exploded illustration;

FIG. 12 shows a detail of the spindle unit from FIG. 11 ;

FIG. 13 shows a detail of the spindle drive assembly from FIG. 1 in a sectional illustration; and

FIG. 14 shows a further detail of the spindle drive assembly from FIG. 1 in a sectional illustration.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a vehicle flap 10, which in the present case is a vehicle hatch or liftgate, having a spindle drive assembly 12 by means of which the vehicle flap 10 can be opened and/or closed.

The spindle drive assembly 12 comprises a spindle drive assembly housing 14 that extends along a spindle drive axis 16.

As can be seen in particular by reference to FIG. 2 , a motor gear unit 18, only schematically illustrated in FIG. 2 , and a spindle unit 20, also only schematically illustrated in FIG. 2 , are arranged in the spindle drive assembly housing 14.

The spindle drive assembly housing 14 here comprises, between its axial ends 14 a, 14 b, a stop section 22 acting axially on both sides.

The motor gear unit 18 is arranged on a first axial side 22 a of the stop section 22 and the spindle unit 20 is arranged on a second axial side 22 b opposite the first axial side 22 a.

Both the motor gear unit 18 and the spindle unit 20 rest against the stop section 22.

In the illustrated embodiment (see in particular FIGS. 3 and 4 ), the motor gear unit 18 is supported in the spindle drive assembly housing 14 by means of two damping elements 24 a, 24 b made from an elastomer.

In addition to a spindle 26 and a spindle nut 28 coupled thereto, the spindle unit 20 comprises a guide tube 30.

In the illustrated embodiment, the guide tube 30 is fastened to the spindle drive assembly housing 14. More precisely, the guide tube 30 is laser welded to the spindle drive assembly housing 14. The laser weld seam 32 is drawn in only schematically here.

The stop section 22 is produced in one piece with the spindle drive assembly housing 14.

Here, the spindle drive assembly housing 14 is made from a plastic material.

In the present case, the stop section 22 is manufactured by injection molding the spindle drive assembly housing 14.

The spindle drive assembly housing 14 additionally comprises a housing cap 14 c. It closes the spindle drive assembly housing 14 on the motor gear unit side.

The housing cap 14 c and the spindle drive assembly housing 14 are laser welded. The laser weld seam 34 is again drawn only schematically here.

The assembly of the spindle drive assembly 12 is performed as follows.

First, the spindle drive assembly housing 14 is provided.

Then the motor gear unit 18 is inserted into the spindle drive assembly housing 14 starting from a first axial side of the spindle drive assembly housing 14 on which, in the example shown, the axial end 14 b is located.

In doing so, the motor gear unit 18 is placed against the first axial side 22 a of the stop section 22.

The spindle unit 20 is inserted into the spindle drive assembly housing 14 from a second axial side 22 b of the spindle drive assembly housing 14 opposite to the first axial side thereof. In the illustrated embodiment, the axial end 14 a is located on this side.

The spindle unit 20 is placed against the second axial side 22 b of the stop section 22.

It is irrelevant to the assembly process whether first the motor gear unit 18 or first the spindle unit 20 is mounted to the spindle drive assembly housing 14. The motor gear unit 18 and the spindle unit 20 may also be mounted essentially simultaneously.

When the spindle unit 20 has been inserted in the spindle drive assembly housing 14, it is fastened in it. In the illustrated embodiment, the spindle unit 20 comprises a guide tube 30 that is fastened to the spindle drive assembly housing 14 by means of the laser weld seam 32.

That is, the spindle drive assembly housing 14 and the guide tube 30 are laser welded.

Subsequently, the spindle drive assembly housing 14 is closed at its end 14 b using a housing cap 14 c. In this context, the spindle drive assembly housing 14 is laser welded to the housing cap 14 c.

The motor gear unit 18 comprises a spindle drive motor 36, which is coupled to a gearing 40 via a motor shaft 38.

FIGS. 5-7 show the spindle drive motor 36 in detail.

With the motor gear unit 18 arranged within the spindle drive assembly housing 14, the spindle drive motor 36 is also positioned within the spindle drive assembly housing 14. The motor shaft 38 here is substantially coaxial with the spindle drive axis 16.

In addition, the spindle drive motor 36 and thus the motor gear unit 18 are supported in the spindle drive assembly housing 14 so as to be rotationally fixed with respect to the spindle drive axis 16 by means of an interlocking fit.

More precisely, the spindle drive motor 36 is supported at the housing cap 14 c in a rotationally fixed manner by means of an interlocking fit, the housing cap being a component part of the spindle drive assembly housing 14.

The rotationally fixed mounting is provided here by means of a motor housing 42 of the spindle drive motor 36.

In the illustrated embodiment, it has two anti-rotation projections 44 a, 44 b provided thereon which, in the assembled state of the spindle drive motor 36 and thus also of the motor gear unit 18, extend substantially along the spindle drive axis 16.

In the present case, the anti-rotation projections 44 a, 44 b are circular cylindrical, with the associated circular cylinder center axes 46 a, 46 b extending substantially parallel to the spindle drive axis 16 in the mounted state of the spindle drive motor 36.

The anti-rotation projections 44 a, 44 b are provided on an axial end side 48 of the spindle drive motor 36 facing away from the motor shaft 38. In the assembled state, the anti-rotation projections 44 a, 44 b are thus positioned on a side of the spindle drive motor 36 opposite to the gearing 40.

In the assembled state, the anti-rotation projections 44 a, 44 b engage in associated recesses 50 a, 50 b provided on the spindle drive assembly housing 14. In the illustrated embodiment, the recesses 50 a, 50 b are provided on the housing cap 14 c.

More precisely, in the illustrated embodiment, the recesses 50 a, 50 b are provided on the damping element 24 b, which is connected to the housing cap 14 c in a rotationally fixed manner.

As an alternative, the anti-rotation projections 44 a, 44 b may engage in the recesses 50 a, 50 b via elastic damping caps arranged on the anti-rotation projections 44 a, 44 b or via elastic damping elements arranged in the recesses 50 a, 50 b.

As is apparent in particular by reference to FIG. 5 , in the illustrated embodiment, besides the anti-rotation projections 44 a, 44 b, a first electrical power connection 52, a second electrical power connection 54 and a sensor connection 56 are additionally provided on the axial end side 48 of the spindle drive motor 36.

FIGS. 8 and 9 show the gearing 40 in detail.

It can be seen here that the gearing 40 is a two-stage epicyclic gearing 58.

In this context, it comprises a first epicyclic gearing stage 58 a, which is also referred to as motor-side or drive-side epicyclic gearing stage 58 a, and a second epicyclic gearing stage 58 b, which is also referred to as spindle-side or driven-side epicyclic gearing stage 58 b.

The epicyclic gearing 58 has helical toothings. Both epicyclic gearing stages 58 a, 58 b have helical toothings in the same direction.

Moreover, the two-stage epicyclic gearing 58 comprises merely one single, singular planet carrier 60, which is thus part of both epicyclic gearing stages 58 a, 58 b.

Furthermore, both the motor-side epicyclic gearing stage 58 a and the spindle-side epicyclic gearing stage 58 b comprise an equal number of planet gears 62 a, 62 b. In the exemplary embodiment shown, each of the epicyclic gearing stages 58 a, 58 b comprises four planet gears 62 a, 62 b.

One respective planet gear 62 a of the first epicyclic gearing stage 58 a and one respective planet gear 62 b of the second epicyclic gearing stage 58 b are mounted on a shared planet gear pin 64.

The planet gears 62 a, 62 b mounted on a shared planet gear pin 64 are connected to each other for joint rotation.

The epicyclic gearing 58 operates as follows.

The motor shaft 38 is rotationally coupled to a sun gear 66 of the motor-side epicyclic gearing stage 58 a. Thus, the sun gear 66 constitutes the drive or torque input of the epicyclic gearing 58.

Since this coupling is effected via a clutch or coupling 68, strictly speaking a gearing input shaft 70 is coupled to the sun gear 66. However, it may be regarded as a continuation of the motor shaft 38.

In the illustrated embodiment, the coupling 68 is an Oldham coupling for compensating an axial offset. FIG. 8 only shows a gearing-side coupling part 69, which is connected with the gearing input shaft 70.

The sun gear 66 cooperates with the planet gears 62 a of the motor-side epicyclic gearing stage 58 a, which in turn are coupled to a ring gear 72 of the motor-side epicyclic gearing stage 58 a.

The ring gear 72 is mounted so as to be rotationally fixed and axially fixed in the spindle drive assembly housing 14 and/or in an epicyclic gearing housing 74. This means that the ring gear 72 is substantially positioned fixed in space.

The motor-side epicyclic gearing stage 58 a is coupled to the spindle-side epicyclic gearing stage 58 b both via the singular planet carrier 60 and via the one-piece planet gears 62 a, 62 b.

Here, the spindle-side epicyclic gearing stage 58 b is constructed without a sun gear.

The planet gears 62 b of the spindle-side epicyclic gearing stage 58 b are only radially supported on an axial bearing extension 76 of the sun gear shaft of the motor-side epicyclic gearing stage 58 a. The sun gear shaft here corresponds to the gearing input shaft 70.

The planet gears 62 b of the spindle-side epicyclic gearing stage 58 b are further coupled to a ring gear 78 of the spindle-side epicyclic gearing stage 58 b.

This ring gear 78 is rotationally coupled to the spindle 26 by means of a coupling 80. The ring gear 78 is mounted for rotation in the spindle drive assembly housing 14 and/or in the epicyclic gearing housing 74.

The ring gear 78 thus constitutes the output or torque output of the epicyclic gearing 58.

The epicyclic gearing 58 can be assembled as follows.

First, all planet gears 62 a, 62 b of the two epicyclic gearing stages 58 a, 58 b are fitted in the singular planet carrier 60.

Subsequently, the planet carrier 60 is inserted into the ring gear 72 of the drive-side epicyclic gearing stage 58 a or into the ring gear 78 of the driven-side epicyclic gearing stage 58 b.

Then, the respective other ring gear, that is, the ring gear 78 or the ring gear 72, is placed on this component assembly.

Thereafter, the epicyclic gearing housing 74 is provided and connected with the ring gear 72.

In the illustrated embodiment, the epicyclic gearing housing 74 is laser welded to the ring gear 72 in a lap joint. For this purpose, the epicyclic gearing housing 74 is laser light transmissive.

For the spindle drive assembly 12 to emit noises when operating that a motor vehicle user will perceive as pleasant, the ratio of the number of teeth of each of the planet gears 62 a of the first epicyclic gearing stage 58 a to the number of teeth of each of the planet gears 62 b of the second epicyclic gearing stage 58 b is selected to be 2:1.

In the illustrated embodiment, each planet gear 62 a of the first epicyclic gearing stage 58 a comprises twelve teeth and each planet gear 62 b of the second epicyclic gearing stage 58 b comprises six teeth.

The ratio of 2:1 corresponds to the interval of an octave when it is based on a ratio of sound frequencies.

Given that the sound frequency emitted by the first epicyclic gearing stage 58 a is decisively determined by the number of teeth of the planet gears 62 a of the first epicyclic gearing stage 58 a and the sound frequency emitted by the second epicyclic gearing stage 58 b is decisively determined by the number of teeth of the planet gears 62 b of the second epicyclic gearing stage 58 b, the spindle drive assembly 12 thus emits sound frequencies in operation which form an octave. This is perceived as particularly pleasant by vehicle users.

In addition, a vehicle user will associate such pleasant noises with a high level of quality of spindle drive assembly 12.

Alternatively, the ratio of the number of teeth of each of the planet gears 62 a of the first epicyclic gearing stage and the number of teeth of each of the planet gears 62 b of the second epicyclic gearing stage may also be selected to be 3:2, 4:3, 5:4, or 6:5.

The emitted sound frequencies then form a fifth, a fourth, a major third or a minor third, respectively. These intervals are also perceived as pleasant by humans.

Generally speaking, the ratio of the number of teeth of each planet gear 62 a of the first epicyclic gearing stage 58 a to the number of teeth of each planet gear 62 b of the second epicyclic gearing stage 58 b is selected such that, in operation, a first sound frequency that is emitted by the first epicyclic gearing stage 58 a differs by an integer multiple of a semitone from a second sound frequency that is emitted by the second epicyclic gearing stage 58 b.

The preferred embodiment of the octave comprises twelve semitone steps, that of the fifth seven, that of the fourth five, that of the major third four and that of the minor third three.

The coupling of the spindle drive motor 36 to the gearing 40, more precisely to the two-stage epicyclic gearing 58, is illustrated in detail in FIG. 10 . Here, the coupling 68 compensating an axial offset and a hysteresis brake 82 are drivingly interposed between the spindle drive motor 36 and the gearing 40.

As already mentioned, the coupling 68 is an Oldham coupling and comprises a coupling part 84 on the drive motor side and the coupling part 69 on the gearing side (see FIG. 8 ).

The two coupling parts 69, 84 are connected to each other via an intermediate coupling part 86 such that the motor shaft 38 and the gearing input shaft 70 are connected to each other for joint rotation.

At the same time, when in the mounted state, the intermediate coupling part 86 is displaceable in relation to the drive motor-side coupling part 84 along a direction 88.

The gearing-side coupling part 69 is displaceable in relation to the intermediate coupling part 86 along a direction 90.

The direction 88 and the direction 90 are substantially orthogonal to each other here. In this way, an axial offset between the motor shaft 38 and the gearing input shaft 70 can be compensated in line with the operating principle of an Oldham coupling.

The hysteresis brake 82 comprises a stationary hysteresis brake component 92, which is fastened to the spindle drive assembly housing 14 and/or to the epicyclic gearing housing 74.

Furthermore, the hysteresis brake 82 includes a rotatable hysteresis brake component 94 rotationally coupled to the motor shaft 38.

The hysteresis brake component 94 is fastened to or integrated in the drive motor-side coupling part 84. More particularly, the rotatable hysteresis brake component 94 is injected into the drive motor-side coupling part 84.

When the spindle drive assembly 12 is viewed perpendicularly to the spindle drive axis 16, the coupling 68 is arranged substantially completely within the hysteresis brake 82 in the axial direction, in particular within the stationary hysteresis brake component 92. The structure of the coupling 68 and the hysteresis brake 82 is therefore especially compact.

FIGS. 11-14 show the spindle unit 20 in detail.

Here, a stop assembly 96 arranged at one axial end of the spindle 26 is adapted to limit a mobility of the spindle nut 28 along the spindle drive axis 16. Specifically, in this way the spindle nut 28 is prevented from moving beyond the end of the spindle 26.

The stop assembly 96 comprises a plastically deformable energy absorption component 97, which in the illustrated embodiment is in the form of an energy absorption sleeve 98, which surrounds the spindle 26 substantially coaxially.

This means that the energy absorption sleeve 98 is mounted at the spindle 26.

The energy absorption sleeve 98 is arranged between a bearing washer 100 on the spindle end side and the spindle nut 28 along the spindle drive axis 16 (see in particular FIG. 14 ).

Moreover, a bearing member 102 is provided between the energy absorption sleeve 98 and the bearing washer 100 to support the spindle 26 at the spindle drive assembly housing 14.

In addition, a thrust washer 104 that is axially displaceable on the spindle 26 is arranged between the energy absorption sleeve 98 and the spindle nut 28.

In the illustrated embodiment, both the bearing washer 100 and the thrust washer 104 are made of a metal material.

At each of its two axial ends, the energy absorption sleeve 98 has a respective collar 106 a, 106 b configured as a force introduction collar.

A deformation section 108 adapted to be upset in the direction of the spindle drive axis 16 is positioned between the collars 106 a, 106 b.

In the illustrated embodiment, the deformation section includes only one single deformation portion. In alternative embodiments, however, it may comprise several, in particular two, deformation portions, with both deformation portions being adapted to be upset in the direction of the spindle drive axis 16.

In a regular operation of the spindle drive assembly 12, the energy absorption sleeve 98 is essentially plastically undeformed (see in particular FIGS. 12 to 14 ). In regular operation, preferably loads on the energy absorption sleeve 98 occur here which exclusively involve forces of less than 750 N.

A load on the energy absorption sleeve 98 with a force of essentially more than 3000 N constitutes an overload event for the illustrated embodiment. This causes the energy absorption sleeve 98 to be plastically deformed.

Such an overload event occurs when the spindle nut 28 runs up against the stop assembly 96, more precisely the energy absorption sleeve 98, at too high a speed and/or too high a force.

This may happen, for example, when the hysteresis brake 82 is defective.

An overload event may also occur during installation of the vehicle flap 10 when the spindle drive assembly 12 is already connected with the vehicle flap 10, but further components of the vehicle flap 10 are still missing. The vehicle flap 10 is then significantly more lightweight than during operation of an associated vehicle, for which the spindle drive assembly 12 is designed. In this connection, the spindle drive assembly 12 may be transferred to an open position by means of a spring that is not further specified. Due to the relatively low weight of the vehicle flap, the spindle nut 28 will then run up against the stop assembly 96 too quickly.

In all overload events, the energy absorption sleeve 98 absorbs the energy resulting from the excessive speed and/or excessive force and thereby protects the other components of the spindle drive assembly group 12 from damage.

FIG. 14 illustrates the spindle nut 28 resting against the energy absorption sleeve 98. However, for reasons of greater clarity, the latter is shown in its plastically undeformed state.

A subsequent operation of the spindle drive assembly 12 in which the opening and closing of the vehicle flap 10 is still possible without any problems is also referred to as an overload sequential operation. In this operating condition the energy absorption sleeve 98 is plastically deformed (not illustrated).

In the event that the energy absorption sleeve 98 comprises a plurality of deformation portions, only one of the deformation portions is plastically deformed in the overload sequential operation.

In case a second overload event occurs subsequently and the energy absorption sleeve 98 comprises a second deformation portion, the latter will deform plastically due to the second overload event. Subsequently, the spindle drive assembly 12 will enter a secondary overload sequential operation, in which the opening and closing of the vehicle flap 10 by means of the spindle drive assembly 12 continues to be ensured. 

The invention claimed is:
 1. A spindle drive assembly for opening and/or closing a vehicle flap, comprising a spindle drive assembly housing which extends along a spindle drive axis and comprises, between its axial ends, a stop section acting axially on both sides, wherein a motor gear unit is arranged on a first axial side of the stop section and wherein a spindle unit is arranged on a second axial side of the stop section opposite the first axial side, wherein the stop section is manufactured in one piece with the spindle drive assembly housing.
 2. The spindle drive assembly according to claim 1, characterized in that the spindle drive assembly housing comprises a housing cap, which closes the spindle drive assembly housing on the motor gear unit side.
 3. The spindle drive assembly according to claim 1, characterized in that the motor gear unit is supported in the spindle drive assembly housing so as to be rotationally fixed with respect to the spindle drive axis.
 4. The spindle drive assembly according to claim 3, characterized in that the motor gear unit is supported in the spindle drive assembly housing by means of a damping element or by means of a plurality of damping elements.
 5. The spindle drive assembly according to claim 1, characterized in that the spindle unit comprises a guide tube fastened in the spindle drive assembly housing.
 6. The spindle drive assembly according to claim 1, characterized in that the spindle drive assembly housing is made from a plastic material.
 7. A vehicle flap, comprising the spindle drive assembly according to claim
 1. 8. The vehicle flap according to claim 7, which is a vehicle hatch or tailgate or vehicle trunk lid.
 9. A method of assembling a spindle drive assembly for opening and/or closing a vehicle flap, comprising steps of: (a) providing a spindle drive assembly housing extending along a spindle drive axis; (b) inserting a motor gear unit into the spindle drive assembly housing starting from a first axial side of the spindle drive assembly housing; and (c) inserting a spindle unit into the spindle drive assembly housing starting from a second axial side of the spindle drive assembly housing opposite the first axial side.
 10. The method according to claim 9, characterized in that the motor gear unit is mounted in the spindle drive assembly housing in a rotationally fixed manner.
 11. The method according to claim 10, characterized in that the motor gear unit is mounted in the spindle drive assembly housing with an interlocking fit.
 12. The method according to claim 9, characterized in that the spindle unit is fastened to the spindle drive assembly housing.
 13. The method according to claim 12, characterized in that a guide tube comprised by the spindle unit is fastened to the spindle drive assembly housing.
 14. The method according to claim 9, characterized in that a housing cap is placed on the spindle drive assembly housing on the motor gear unit side, so that the housing cap closes the spindle drive assembly housing.
 15. The method according to claim 14, characterized in that the housing cap is fastened inside the spindle drive assembly housing.
 16. The method according to claim 9, characterized in that a stop section acting axially on both sides is provided at the spindle drive assembly housing and the motor gear unit is placed against a first axial side of the stop section.
 17. The method according to claim 9, characterized in that a stop section acting axially on both sides is provided at the spindle drive assembly housing and the spindle unit is placed against a second axial side of the stop section opposite the first axial side. 